The present disclosure relates to, for example, semiconductor devices applicable to powering, etc.
Higher efficiency in power semiconductor modules for power conversion is demanded in view of low energy consumption.
Most of heat generated in power semiconductor modules in operation is generated from semiconductor elements. In order to reduce the inductance between ground and power sources in half bridge structures to the limit, optimization in the structures of power semiconductor modules is also demanded. To achieve the objective, most suitable structures of power semiconductor modules formed by closely arranging a plurality of semiconductor chips are considered from both the heat and electrical points of view.
FIG. 5 illustrates an example structure of such a conventional power semiconductor module.
As shown in FIG. 5, in the conventional power semiconductor module, a gate terminal 128 and a source terminal 129 provided in a semiconductor module 118 inside a case 116 are electrically connected to a drive element 106 mounted on a control board 208 via a shortest path. Inside the semiconductor module 118, a gate pad and a source pad of a semiconductor element 110 are connected to the gate terminal 128 and the source terminal 129 via wires 109. In the conventional power semiconductor module, control signals converted by a photocoupler 103 mounted on a control board 201 are transmitted to the drive element 106. The control board 208 is electrically connected to the control board 201 by a lead 204. If the lead 204 is long and fine, the ground potential of the control board 208 and the ground potential of the control board 201 fluctuate to easily generate noise. To address the problem, in the conventional structure, the control board 208 is located as close as possible to the control board 201 to reduce the length of the lead 204.
In order to reduce the influence of the lead 204, as shown in FIG. 6A, a conventional semiconductor module is considered, in which a photocoupler 103 and a drive element 106 are mounted close to one another on a same control board 218. In the structure of FIG. 6A, drive signals generated by a control board 211 located above the control board 218 are input to the control board 218 via a lead 214. FIG. 6B illustrates example arrangement of specific components of the control board 218. As shown in FIG. 6B, in each conventional semiconductor module, a photocoupler 103 is located as close as possible to a drive element 106.
Although each of the structures shown in FIGS. 6A and 6B reduces the influence of noise, the temperature of the photocoupler 103 may rise, since the photocoupler 103 is mounted on the control board 218 together with the drive element 106.
In order to reduce the influence of heat, providing a shield between two control boards is considered (see, e.g., Japanese Unexamined Patent Publication No. 2001-237368).